In one of my earlier roles, I was responsible for a system used to filter internet access for about a million school students. The students were absolutely easily able to bypass our filtering in a bunch of ways we could not address, as we had no control over the client devices.
Being a team of professionals in a situation where we were constantly being defeated by a bunch of kids felt humiliating, even as we acknowledged the uneven battleground we were fighting on.
I suspect a similar feeling was behind this blog post. Why else say things like "as much as we might like the idea of an ever-escalating appsec war with teenagers"? This comes off as bitter and insincere to me. As though they're trying to put down their adversary while simultaneously acknowledging they're losing the battle and need to deploy the nuclear option.
Edit: not that "teenager" is necessarily a put down. If there's one thing I learned from that job, it's that teenagers are incredibly resourceful.